Alex - u live in the wrong country for some deep dish rims. You gotta move to europe, since it is a very common thing to do. over here no one has them, or are very hard to find
nordy - u r partially right. but nothing is impossible. Ever seen a focus with 17x9 front (215/40/17)/17x10 rear (245/35/17) and a 26mm offset??? Click on the link below.
Cy - maybe over here people do not put deep dishers on, but as I said before, there are alot of people back home in germany that are running deep dishes. But also check this link where I replied with examples:
Those wheels went on on both cars without any modifications to the fenders or anything else. Just cuz ford says a certain offset is perfect for the focus, does not mean that other do not work at all. Back home it is a commom thing, and to be honest with you, I only experienced alot better handling with with lower offsets and wider track.